Re: Firefox won't find available plugins in ubuntu 12.04

You can manually install plugins using either the Ubuntu Software Centre or via the website of the plugin. If it is Adobe Flash, you may be out of luck due to lack of support from Adobe. Google Chrome does include a flash plugin though, so that might be an option if you need it. If Java is required, you should be able to install openjre using Ubuntu Software Centre - have a look for the default-jre package.